1. Field of the Invention
The present invention relates to a measuring apparatus for measuring a measurement target, and particularly relates to a measuring apparatus for measuring a measurement target by use of a light beam.
2. Description of the Related Art
Some wafers, for example, are known to be provided with ball-shaped terminals (referred to below as bumps) formed by soldering or the like to provide wiring for each electronic component. As one of inspections for the electronic components, such wafers before dicing are inspected by measuring the height of each bump. To measure the height of a bump, the following type of measuring apparatus has been employed (see JP-A 2000-266523, for example). Specifically, in this apparatus, a wafer as a measurement target is irradiated with a laser beam or the like (referred to below as a line beam), an image of the part irradiated with the line beam is picked up by an imaging device, and the heights in certain parts of the wafer, that is, the heights of the bumps and the like are measured by use of the image data. In this measuring apparatus, an optical imaging system is provided between the imaging device and the measurement target. The optical imaging system is set so that the imaging device is capable of picking up an image of the part irradiated with the line beam.
From the viewpoint of manufacturing efficiency of a measurement target (a wafer in the above example), in the measurement of the measurement target, it is required to make time required for measuring (referred to below as measuring time) as short as possible while maintaining a certain accuracy. For this reason, in the above-mentioned optical imaging system, an optical setting is determined for an object for measurement (each bump in the example above) in the measurement target to make the measuring time as short as possible while maintaining certain accuracy.
However, the apparatus described above has a limitation on the speed at which the imagining device performs output processing on acquired data, and thus also has a limitation on the shortening of the measuring time if a certain accuracy is to be maintained.